To the Editor.—The pulsed neodymium YAG laser used within the human eye requires aiming and focusing techniques that differ from conventional laser photocoagulation. Specifically, the focal spot distorts when the laser enters the cornea through an eccentric portion or at an oblique angle; chromatic aberration causes separation between the helium neon focus and the neodymium YAG focus; and, finally, focusing the laser on a posterior capsule to spare a lens implant requires a critical attention to detail.To facilitate practice by the beginning laser surgeon, a model eye was built that mimics the important physical features of the eye.The model eye (Fig 1) is made of lucite with an artificial 45 diopter cornea of 0.5 mm. The eye is available with a clear posterior and side wall to facilitate studies of throughput energy and the laser breakdown zone. A holder (Fig 2) clamps to the slit-lamp headrest to